The Spanish word 'pedernal' (meaning 'flint') traces back to ancient Greek 'petra' meaning 'rock' or 'stone', which was borrowed into Latin with the same meaning. In Latin, the adjective 'petrinus' was formed meaning 'of stone'. When this word entered Spanish, it combined with the suffix '-al' (meaning 'relating to') and underwent some sound changes, with 'tr' becoming 'dr', ultimately developing into 'pedernal' specifically referring to flint stone.

Some related Spanish words include 'piedra' (stone), which comes from the same Latin root 'petra', and 'pedregal' (rocky ground). These words maintain the basic meaning of 'stone' or 'rock' while 'pedernal' specifically evolved to refer to flint, a particular type of stone.

English speakers might recognize this connection in words like 'petrify' (to turn to stone), 'petroleum' (literally 'rock oil'), and 'Peter' (a name meaning 'rock'). All these words share the same ancient Greek root 'petra'. The scientific term 'petrology' (the study of rocks) also comes from this root.